1. Field of the Invention
This invention relates generally to ratios of isomers formed on N-substitution of asymmetric imidazoles. More particularly, it relates to the preparation of novel compounds including some of those disclosed in both the aforementioned parents of this continuation-in-part application. It also relates to the novel mixtures thereby obtained, as well as to other related processes.
2. Related Art
There is extensive prior art relating to the tautomeric character of asymmetric imidazoles containing a free imino hydrogen (i.e. imidazoles containing a substituent in the 4- or 5-position, or two dissimilar substituents in these positions). There is also prior art relating to the ratio of isomers formed on methylation of imidazoles under varying conditions. For example, see Imidazole and its derivatives Part I by K. Hofmann, published by Interscience Publishers (1953), at pages 26-30 and also "Advances in Imidazole Chemistry" by M. R. Grimmett in Advances in Heterocyclic Chemistry, Volume 27, published by Academic Press (1980), at pages 288-297. However, such known prior art does not disclose the novel products claimed hereinafter nor the specific processes to make them.
Arthur C. Bayer's pending application Ser. No. 589,608, filed Mar. 14, 1984, discloses sodium salts of some asymmetric imidazoles (see page 3, middle of the page; Examples 23 and 26 in Table 1 at page 6; and all claims). However, Examples 23 and 26 do not indicate which particular sodium base was used to prepare the salts. Nor is any ratio given for the "two resonance forms Ia and IIa" on page 3 prepared by proton removal with "any" base.
The related art also includes descriptions of the preparation of imidazole derivatives in the presence of sodium hydride. However, all such references appear to be irrelevant because they relate to non-asymmetric imidazoles, etc.
Essentially, nowhere does the now-known prior art disclose or suggest the process claimed hereinafter wherein pairs of novel compounds are prepared in preselected ratios.